Spain is a major producer of fresh oranges which are consumed throughout Europe. Disease infections in the citrus orchards can result in spots on the orange peel with no damage to the fruit inside. However, consumers will not pay top price for spotted oranges making fungicide use necessary.
“Alternaria brown spot (ABS) is a severe fungal disease of some mandarins and their hybrids in rainy and semiarid citrus-growing areas. … The presence of ABS in Spain has become a serious problem for ‘Fortune’ mandarin production.”
“Defoliation due to spring infections weakens trees and has an important impact on yield. However, fruit damage causes the most important economic losses. Fruit symptoms include light brown, slightly depressed spots to circular and dark brown areas on the external surface.”
“Although cultural practices that improve ventilation and prevent the growth of lush foliage can greatly reduce disease severity in the orchard, fungicide applications are essential to produce quality fruit for the fresh market. One or two sprays generally are needed to protect spring flush foliage to reduce defoliation and prevent inoculum build-up.”
Authors: A. Vicent, J. Armengol and J. García-Jiménez
Affiliation: Instituto Agroforestal Mediterráneo, Universidad Politécnica de Valencia, Valencia, Spain
Title: Rain fastness and persistence of fungicides for control of Alternaria brown spot of citrus.
Publication: Plant Disease. 2007. 91(4):393-399.